1. Field of the Invention
This invention relates to a binding structure, more particularly, to a binding structure for binding a stack of sheets to form a book or the like.
2. Description of the Related Art
A traditional hard cover bound book typically has front and back hard covers connected to a hard spine. Because the bound book can create valleys between pages, warping line text or distorting images on the pages, readers have to press down the pages in an attempt to alleviate reading discomfort and to create a flatter reading surface. Furthermore, arched pages in the traditional hard cover book are relatively more likely to be flipped by breezes if no weight is applied to their surface. Besides, when such a hard cover bound book is opened, the traditional hard spine fixed between the front and back covers becomes an obstacle in book cover design so that designers must design around. Some solutions to this problem are to use a slip-cover that is made of a piece of paper separated from the book covers and that has a continuous outer surface area for design, or to provide design elements only on the front and back covers to optically downplay the spine. However, these solutions still have room for improvement.
One such improvement is to use a piece of book cloth covering a soft spine, and front and back covers, with excess cloth portions spanning gaps between the edges of the spine and the front and back covers. The excess cloth portions form hinge connections for the spine and the front and back covers, which allow the soft spine to drop away from the covers when the book is opened. Since the spine is covered by the book cloth and is relatively soft, the book can open flat and lay flat on a surface, thereby eliminating arches of pages and valleys in between pages. However, the spine is still showing and becomes a protrusion from the otherwise flat surface of the covers. This makes the spine harder to design around when designing book covers.
An other improvement that enables a book to be opened flat utilizes a coil as a binding structure. Holes are punched in one side of covers and pages, and a plastic or metal coil is wound through the holes, binding the covers and pages together. Such a binding structure is aesthetically and structurally inferior to traditional spines in that the coil protrudes in between the pages when the book is opened flat, and that there is a high risk of covers or pages tearing out because the punctured holes are within close proximity to one another.